I first identify rare types (<20 occurrences) and identify the types they optimally should be grouped with. I usually combined types within not across ecoregions.
##
## RT11_Steppic RT6_Steppic RT1_Arctic RT12_Boreal RT10_Boreal
## 1 1 2 2 3
## RT5_Anatolian RT7_Steppic RT11_Outside RT4_Outside RT8_Arctic
## 3 4 6 6 7
## RT11_Anatolian RT8_Pannonian RT11_BlackSea RT12_Anatolian RT12_BlackSea
## 10 11 12 12 13
## RT12_Outside
## 13I keep the rare RT1-based types, as very large rivers are quite distinct (e.g. Borgwardt et al. 2019).
In the following, I address the rare types ordered by ecoregions.
The Anatolian region includes nine of twelve river types. The missing types are lowland rivers (with the exception of RT1 and 5).
The two Mediterranean types (RT11 and 12) are rare. However, together they encompass 22 segments, which I consider sufficient. Hence, I combine these two types.
Lowland types are absent besides very large rivers (RT1) and three segments of small siliceous lowland river (RT5).
The three segments of RT5 are consecutive and belong to one river, close to the southern coast of Turkey. Based on topographic maps, I reckon that these segments are classified erroneously. The northern most segment is above 800m for most of its course and the middle segment is above 200m. Therefore, I reclassify them into RT10 and RT9. The last segment, which is correctly classified, is removed from the data set.
The Arctic region covers Iceland, Svalbard and parts of northern Norway and Russia. It includes six river types and lacks any Mediterranean or calcareous rivers. Two of the six types have less than 20 segments: RT1 and RT8. The very large rivers are left as is.
The mid-altitude siliceous large river segments belong to two rivers in Norway. Both merge with a lowland siliceous small river into large lowland siliceous rivers. I will re-designate them as lowland siliceous small rivers (RT5).
The Black Sea ecoregion covers the south, west and east sides of the Black sea, with the exception of the Bosporus. This relatively small region contains all 12 river types and only two are rare (i.e. less than 20 segments). The rare types are the two Mediterranean types which we will combine.
The Boreal region is among the largest biogeographic regions. It encompasses all but one broad river type: Perennial Mediterranen (RT11). Two of the types are rare: RT10 and RT12. The three highland (RT10) segments are of siliceous geology and hence I combine them with the mid-altitude small siliceous rivers (RT9). I suspect the two Mediterranean segments (RT12) are supposed to designate temporary rivers, however this is not consistent with the definition given in Lyche Solheim et al. (2019). Given this incongruence, I remove these segments from the data set.
##
## RT1_Boreal RT10_Boreal RT12_Boreal RT2_Boreal RT3_Boreal RT4_Boreal
## 3239 3 2 9825 5321 19278
## RT5_Boreal RT6_Boreal RT7_Boreal RT8_Boreal RT9_Boreal
## 14634 530 453 5197 5006The polygon shapefile of the biogeographic regions contains a large area which is simply titled: “outside.” This region is a filler and does not contain useful information. I remove all river segments that fill within this type.
The Panonnian basin contains ten broad river types. It lacks high altitude rivers and perennial Mediterranean rivers. The RT8 rivers are joined with the RT9 rivers.
##
## RT1_Pannonian RT12_Pannonian RT2_Pannonian RT3_Pannonian RT4_Pannonian
## 459 89 1867 1250 386
## RT5_Pannonian RT6_Pannonian RT7_Pannonian RT8_Pannonian RT9_Pannonian
## 243 71 136 11 78The Steppic region covers the eastern part of Romania, Moldavia, most of Ukrain including the Krim and extends to the all the way to the Caspian sea. The intersection with the broad river types only covers the Romanian part however. In includes nine river types, three of which are rare. The are many Mediterranean-type rivers (RT11 and RT12) in the Steppic biogeographic region. The temporary type (RT12) is the third most common type (184 rivers segments, ~12% of segments) in this region. There is only one perennial Mediterranean river segments (RT11) which I combine with the temporary segments.
Both mid-altitude calcareous types (RT6 and RT7) are rare, with one and four instances respectively. I combine them with the calcareous lowland types (RT2 and RT3).
##
## RT1_Steppic RT11_Steppic RT12_Steppic RT2_Steppic RT3_Steppic RT4_Steppic
## 103 1 184 558 616 29
## RT5_Steppic RT6_Steppic RT7_Steppic
## 42 1 4## R version 4.1.0 (2021-05-18)
## Platform: x86_64-w64-mingw32/x64 (64-bit)
## Running under: Windows 10 x64 (build 19042)
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## Matrix products: default
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## [3] LC_MONETARY=German_Germany.1252 LC_NUMERIC=C
## [5] LC_TIME=German_Germany.1252
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## attached base packages:
## [1] stats graphics grDevices utils datasets methods base
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## [1] stringr_1.4.0 tmap_3.3-2 dplyr_1.0.7 magrittr_2.0.1 sf_1.0-2
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## loaded via a namespace (and not attached):
## [1] tidyselect_1.1.1 xfun_0.24 bslib_0.2.5.1
## [4] purrr_0.3.4 lattice_0.20-44 leaflet.providers_1.9.0
## [7] vctrs_0.3.8 generics_0.1.0 viridisLite_0.4.0
## [10] htmltools_0.5.1.1 stars_0.5-3 s2_1.0.6
## [13] base64enc_0.1-3 yaml_2.2.1 utf8_1.2.2
## [16] XML_3.99-0.6 rlang_0.4.11 e1071_1.7-8
## [19] jquerylib_0.1.4 pillar_1.6.2 glue_1.4.2
## [22] DBI_1.1.1 sp_1.4-5 RColorBrewer_1.1-2
## [25] wk_0.5.0 lifecycle_1.0.0 raster_3.4-13
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## [34] parallel_4.1.0 class_7.3-19 fansi_0.5.0
## [37] leafem_0.1.6 Rcpp_1.0.7 KernSmooth_2.23-20
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## [43] jsonlite_1.7.2 abind_1.4-5 png_0.1-7
## [46] digest_0.6.27 stringi_1.7.3 tmaptools_3.1-1
## [49] grid_4.1.0 tools_4.1.0 sass_0.4.0
## [52] proxy_0.4-26 tibble_3.1.3 dichromat_2.0-0
## [55] pacman_0.5.1 crayon_1.4.1 pkgconfig_2.0.3
## [58] ellipsis_0.3.2 assertthat_0.2.1 rmarkdown_2.9
## [61] R6_2.5.0 units_0.7-2 compiler_4.1.0